Zeaxanthin is a carotenoid with high antioxidant activity. It is found in high concentrations in the macula of the eye. Studies supporting the use of zeaxanthin supplements to prevent/improve certain health conditions. Macular degeneration and cataracts, among others.
What is Zeaxanthin?
Zeaxanthin is a pigment present in nature as an organic constituent of tagetes and calendula plant species. Plants mainly from the marigold and marigold as the most outstanding species in terms of their composition in this pigment.
Additionally, its significant presence in bell peppers and other Mexican peppers cannot be forgotten.
Zeaxanthin is, together with lutein, one of the greatest exponents of natural food pigmentation, which, on a large scale, is due to a general group of substances known as carotenoids.
The existence of this type of compound is vital within the plant metabolism. This is due to their function as promoters of photosynthesis and as filters of ultraviolet radiation. It prevents an excess absorption of high frequency energy ‘quantums’ that could damage the plant’s organism.
Within the classification of carotenoids, the subgroup of xanthophylls stands out. The main characteristic is to give the species that carry them a yellowish or brownish shade. Within the xanthophylls we can mention:
- Zeaxanthin: yellow fat-soluble pigment structurally present in different biological kingdoms, as protists in (algae), monera (bacteria), plants and animals. The common denominator that justifies their existence is to act as a shield against solar radiation. In the human species, this means protecting the retina from ultraviolet radiation.
- Lutein: With similar properties to zeaxanthin.
- Capsanthin: It is an excellent antioxidant present in red pepper in association with other similar pigments such as capsaicin
As a chemical compound, once extracted and purified, zeaxanthin takes the form of an orange-reddish crystalline powder. It is almost insoluble in water and practically odourless. It is necessary to raise the temperature to 207 ºC for its transition to a liquid state.
Lutein and zeaxanthin
Its action within the ocular machinery is based on preventing the triggering of chemical reactions that lead to the formation of free radicals. These are enormously harmful to the soft tissues and especially the parts of the eyeball.
This strong antioxidant action results in a very specific benefit in terms of ophthalmic pathology. The prevention of the dreaded macular degeneration, an insidious and irreversible process linked to age and the opacity of the lens. Adequate intake of lutein and zeaxanthin reduces the risk of developing cataracts by up to 20% and of macular degeneration by 40%.
As both members of the carotenoid group, there are serious links between zeaxanthin and betacarotene, The metabolic route followed by the organism for its use is not included.
While the second behaves as a precursor to vitamin A, a molecule into which it is transformed and after which it is stored as a reserve substance in the liver, zeaxanthin is distributed mainly, while maintaining its chemical identity, in the macula of the retina and the crystalline lens.
Zeaxanthin in food
Additionally, it can be found in significant concentrations in asparagus, pepper, orange, persimmon and tangerine. For vegetables, one formula for maximum absorption is to ‘steam’ or eat them raw.
For optimum absorption, it is also recommended that the zeaxanthin source be accompanied by a food with a fat is at least appreciable, given the liposolubility of the pigment.
An excellent alternative is to combine them with olive oil in the case of salad vegetables. And for animal products, the most important is egg yolk (provides 0.25 milligrams).
Recent research has revealed interesting conclusions regarding the efficiency of the organic absorption of this pigment, fortunately it is known that nicotine addiction is clearly a factor inhibiting the absorption of carotenoids in general and of zeaxanthin in particular, increasing the risk of suffering adverse reactions as a result of zeaxanthin supplementation.
It can also be said that some margarines whose composition involves plant sterols are recognised as having the capacity to hinder the absorption process of zeaxanthin.
Although the prolonged consumption of high quantities of this pigment lacks conclusive clinical data about its effects. The European Food Safety Authority carried out a sufficiently scientifically rigorous assessment showing that daily intake should not exceed one mg per kilogram of body weight.
Dosage of zeaxanthin
People diagnosed with macular degeneration may take up to 10 mg of zeaxanthin daily.
For people with ingrained habits of tobacco or alcohol consumption or drinking, and those whose diet is not dominated by fruit and vegetables, the need for exogenous zeaxanthin is greater.
In turn, supplementation may be necessary in patients suffering from pancreatic or liver failure, Crohn’s disease, celiac disease (gluten intolerance) or who have had their gallbladder removed.
Properties of Zeaxanthin
The human body lacks genetic programming to synthesise this substance, so it depends strictly on a permanent exogenous contribution, since its presence is essential for its correct functioning.
Against free radicals
In fact, its modus operandi can be represented as the formation of a shield in the retinal macula, by which the cells are protected from the high frequencies present in each beam of light.
Prevention of cataracts
Likewise, its effects in preventing the formation of cataracts have been widely contrasted, having established a cause-effect relationship between a lack or insufficiency of zeaxanthin and the genesis of this deterioration of the crystalline lens.
Its antioxidant power contributes to improving the condition of artery walls, making it a significant weapon in the prevention of cardiovascular diseases, one of the three main causes of death in developed countries.
Possible reduction of illness
For their part, various types of cancer, mostly located in the respiratory system (larynx, pharynx and lung), admit a certain degree of reduction in the risk of occurrence with an adequate presence of zeaxanthin in the body, as revealed by certain epidemiological studies.
It should be noted that this pigment also has a role, if you want more secondary, in the prevention of common diseases such as flu or tooth decay. And even according to certain research that still lacks sufficient contrast, it could help prevent Alzheimer’s and senile dementia.
Anti-inflammatory and anti-ageing
The intervention of free radicals as predisposing agents for cell damage is not limited to the eye area. Therefore, zeaxanthin is able to muffle the effects of inflammatory processes and fight ageing by preventing damage at the membrane level.
The skin, which is highly exposed to the effects of ultraviolet radiation, clearly responds to the benefits of a diet rich in foods with plenty of zeaxanthin, which can help protect it from oxidative damage caused by free radicals.
Zeaxanthin and vision
In the field of nutrition, it has become a major player as a nutraceutical agent because of its proven benefits for visual health, since January 2013, when the European Union opened the way for the introduction of synthetic zeaxanthin on the market.
But a synergy between a healthy diet rich in carotenoid-containing foods and regular intake of xanthophyll supplements seems to be the ideal formula for maximum benefit.
But it is not only from the point of view of their physiological contribution that their virtues should be noted. In the food industry, for example, its antioxidant properties give it the proven ability to prevent soya oil from going rancid.
Effects of these foods
In the agricultural field, one of the most striking influences is that it produces in the maize. In its grain it contributes effectively to stop the proliferation of the species of fungi that produce aflatoxins, metabolites that require environmental conditions of favorable humidity and temperature and that once they contaminate the corn become a great threat to health through the food products in which this cereal participates.
There is an orange colour that it transmits to the raw materials in the manufacturing of multiple food products. We will mention bakery products, processed cereals, infant formula, fruit juices and nectars. Also jellies and marmalades, soups and creams, chewing gums, etc.
And as regards the formulation of compound feed for poultry (both egg and meat production). It is indispensable to achieve the shade for the egg yolk and the chicken skin.
Side effects of zeaxanthin
This pigment, reasonably consumed, has hardly any recognised side effects, and is therefore considered to be of high food safety. Purified zeaxanthin is included in the list of GRAS substances (generally recognised as safe), based on toxicity studies in animals.
Shared side effects have occasionally been described with multivitamin complexes and minerals como malestar gástrico, cefalea y sabor extraño.
Combinations with zeaxanthin
Zeaxanthin, like lutein, does not meet the requirements for classification as an essential nutrient. This depends on whether it has been shown to be necessary for growth or the maintenance of health. On the other hand, insufficient intake has not been documented to result in deficiency disorders or death.
In 2013 the European Commission determined that the introduction of synthetic zeaxanthin into the market was justified. This marked the start of the manufacture of pharmaceutical and nutritional preparations in which it is the main active ingredient.
Vitamin C and E
As for food practices that can be highly beneficial, we can say that vitamin C and E are nutrients which have demonstrated a good synergy with zeaxanthin for the preservation of the integrity of the ocular tissues.
Salad mixes with spinach, tomato, carrot, corn, egg, oil and lemon or orange juice are ideal.
This property gives natural astaxanthin its uniqueness compared to other substances, nor does beta-carotene.
The polyunsaturated fatty acids called omega 3 also play an important role in this dynamic. The chemical composition of the plasma membrane of the specialised vision cells (cones and rods) is very abundant in one of them, docosahexaenoic acid.
- Kumari N, Cher J, Chua E, Hamzah H, Wong TY, Cheung CY. Association of serum lutein and zeaxanthin with quantitative measures of retinal vascular parameters. PLoS One. 2018 Sep 27;13(9):e0203868. doi: 10.1371/journal.pone.0203868. eCollection 2018.
- Wu J, Ji X, Tian S, Wang S, Liu H. Ectopic expression of a Citrus kinokuni β-carotene hydroxylase gene (chyb) promotes UV and oxidative stress resistance by metabolic engineering of zeaxanthin in tobacco. 3 Biotech. 2018 Nov;8(11):450. doi: 10.1007/s13205-018-1440-7. Epub 2018 Oct 15.